I rank ordered every weapon in the game for the following parameters:
a) Damage done per ton of weight
b) Damage done per heat generated
c) Heat generated per second of game time at max fire rate
d) Damage done per second (DPS) at max fire rate
Note that I am not including the indirect fire weapons....damned if I know how to figure them out.

The Tesla does the most damage, at 25, and only takes 15 seconds to recycle.... 1.67 dmg per second.
The cold light gun and pulse laser are the only two other ranged weapons doing potentially better than 1 damage per second.
Close combat weapons, in order of best to worst, chainsaw poweraxe, then flamethrower...all 1.5 to 1.0.
Weapons that generate the LEAST heat per second (HPS):
a) Machine gun, at .33 HPS
b) SRM-4, at .38 HPS
Weapons that generate the GREATEST HPS:
a) Medium laser, at 2.10 HPS
b) Large laser, at 2.09
c) Plasma gun, at 2.06
Not surprisingly, beam weapons are all over the top ten.
One last comment...the tesla bolt does 1.67 DPS takes up four slots.
Factor this in, the best DPS/slot is the medium laser, at .86
Soooooo......I made an assault titan with TONS of med. lasers, and threw in an "A" heat regulator...and STILL overheat! Heh, but it will KILL any 40T titan out there!
MAN this game is fun!